-LRB- CNN -RRB- -- The Space Shuttle Discovery launched late Thursday afternoon from Kennedy Space Center in Florida , marking the start of its 39th and final flight .

`` This was a pretty successful day , '' said Bill Gerstenmaier , NASA 's associate administrator for space operations . `` It was just an amazing event . ''

The six-member crew will deliver a storage module , a science rig and spare parts to the international space station during its 11-day mission .

Originally scheduled for November , Discovery 's launch had been delayed in order to make repairs to the external tank 's support beams .

And NASA halted its countdown on Thursday , at five minutes , because of a computer problem related to safety on the `` eastern range . '' But after a confirmation that all was good to go , the countdown resumed , and the shuttle lifted off about three minutes behind its planned 4:50 p.m. ET launch .

Five minutes in , NASA 's official blog reported `` a good separation for solid rocket boosters , '' which separated from the main shuttle after pushing the shuttle through Earth 's lower atmosphere . Shortly thereafter , the blog reported that the Discovery and its astronauts were `` safely in orbit , '' having `` performed flawlessly '' on its launch .

Gerstenmaier noted , and video showed , four pieces of foam tearing apart from the shuttle about four minutes into launch . But the NASA administrator called these incidents `` typical '' and likely harmless , since they came off `` after the area of concern '' when the atmosphere was so thin to make its impact negligible .

The crew is headed by Steve Lindsey , and includes a late addition in Steve Bowen -- who became the first ever astronaut to fly consecutive missions after he was assigned to take the place of Tim Kopra , when Kopra was injured last month in a bicycle accident , according to NASA .

Prior to Thursday 's launch , Discovery had spent 352 days in orbit , circling the Earth 5,628 times . It has also carried 246 crew members , more than any space vehicle in history .

`` In a way , it 's ... sad to see the last flight , '' said astronaut Steven Swanson . `` It 's such a wonderful vehicle . ''

The last scheduled launch of Space Shuttle Endeavour is set for April 19 and will be commanded by Mark Kelly , the husband of U.S. Rep. Gabrielle Giffords , who is recovering from being shot last month in Tucson , Arizona . Atlantis is tentatively scheduled to launch during the summer .

The 30-year shuttle program should have ended a long time ago , NASA 's administrator told CNN on Wednesday .

`` What is not acceptable is the fact that the most powerful nation in the world , the United States of America , finds itself in a situation that we did n't do the proper planning to have a vehicle in place to replace shuttle when it lands its last landing , '' Charles Bolden said .

Bolden hopes that at least two commercial space companies will emerge to transport astronauts to the International Space Station . This will allow NASA to concentrate on building a new heavy-lift rocket capable of leaving lower Earth orbit .

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NEW : A NASA official describes Thursday 's launch as `` an amazing event ''

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NEW : The 4 pieces of foam that fell off the shuttle are n't considered dangerous

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Discovery , on its 39th flight , is part of a shuttle fleet that is being retired

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Its crew will deliver a storage module and other items to the space station